Lifting mechanism for sliding doors



Seafch Oct. 9, 1945. F. nucl-FIELD LIFTING MECHANISM FOR SLIDING DOORS Filed Feb. l0, 1944 o o 0 0 0 @TM W o o 0 o G o o 191 |l/ u w? Q i# ,w N 0 ILL J. W W 0 o o wwwa a l5. MISCtLLANtUU rimwww'- Patented Oct. 9, 1945 LIF'IING MECHANISM FOR SLIDING DOORS Frank Ditchiield, Cleveland, Ohio, assignor to The Youngstown Steel Door Company, Cleveland, Ohio, a corporation of Ohio Application February 10, 1944, Serial No. 521,763

7 Claims.

This invention relates to lifting mechanism for sliding doors, particularly for sliding doors of railway house cars.

It is an object of this invention to provide mechanism for lifting sliding doors above a frictional door supporting member and supporting said doors upon anti-friction means during opening and closing movements which shall eliminate a substantial amount of the friction encountered in similar lifting mechanisms.

A further object is to provide lifting mechanism of the character stated above which shall be double-acting.

Other objects of the invention will become clear as the description thereof proceeds.

In the drawing forming part of this specification:

Fig. 1 is a fragmentary elevation of a sliding car door equipped with a lifting mechanism ernbodying the instant invention.

Fig. 2 is a vertical section taken on line 2-2 of Fig. 1. f

Fig. 3 is an enlarged detail of a portion of the lifting mechanism of Fig. 1.

Referring to the drawing, a sliding door I for railway house cars is shown for the purpose of illustrating the instant invention. This door embodies a metallic panel formed with horizontal corrugations I2 and reinforced along its vertical margins by means of members generally indicated by the reference numerals |3 and I4. The lower margin of the panel is offset outwardly as indicated at I5 to provide a depending vertical flange I6 spaced outwardly from the main plane of the panel. The ange I6 cooperates with a backing plate |1 fastened to the panel above the outwardly offset portion I5 and a Z-shaped member I9 to provide a box section within which the lifting mechanism of the instant invention is housed. The vertical ange I6 of the panel is fastened to the upstanding leg I9 of the Z-shaped member I8 and the backing plate I1 is fastened to the depending leg 20 of the Z-shaped member.

The web 2| of the Z-shaped member I8 is accordingly disposed in a substantially horizontal plane and is utilized to frictionally support the door when in lowered position upon a substantially channel-shaped track 22 secured to the reinforcement 23 for the side sill 24 by means of a `plurality of brackets one of which is indicated at 2l.

The lifting mechanism of the instant invention embodies spaced substantially H-shaped roller housings 29--24 which, as more clearly shown in Fig. 1 of the drawing, are disposed in an inclined position. Each of the roller housings is provided with alined trunnions 21 and 23. The trunnion 21 extends through a vertical slot 29 formed in the flange I6 of the door panel and in the vertical leg 30 of an angle member 3| secured to the inner face of flange I6. The angle member 3| is formed with a substantially horizontal leg 32 as more clearly appears from Fig. 2 of the drawing.

The trunnion 28 extends into a similar alined vertical slot 33 formed in the backing plate I1 and in a plate member 34 secured to the backing plate as shown in Fig. 2 of the drawing.

A main door supporting roller 35 is mounted between the lower branches 39 and 31 of each of the roller housings 26 by means of a pin 38 the ends of which are supported in the lower branches. Similarly, a roller 39 is supported be tween the upper branches 40 and 4I of each of the H-shaped roller housings by means of a pin 42 in proximate relationship to the underside of the horizontal leg 32 of the angle member 3|. The pins 42 are so disposed that they are the same distance from the center line of the trunnions 21 and 28 as the pins 38.

In order to operate the lifting mechanism, a lever 43 is mounted upon one of the trunnions 21 which, as more clearly shown in Fig. 2 of the drawing, projects outwardly of the door for this purpose. The lever 43 is formed with hand grips 44 and 45 for a purpose which will hereinafter appear.

It is preferred that the operation of the roller housings be simultaneous to insure even lifting of the door and for this purpose a bar 46 mounted upon the pins 42 is utilized to connect the roller housings.

As more clearly shown in Fig. 2 of the drawing, the rollers 35 engage the track 22 and for this purpose slots such as 41 are provided in the web 2| of tie bottom Z-shaped memberv I9.

The door is shown in the drawing in its lowered position ir frictional engagement with the track 22. To move the door toward the right as viewed in Fig. 1 of the drawing, the handle 44 is grasped and the lever 43 moved in clockwise direction. Such movement causes rotation of the roller housing to which the lever is secured in clockwise direction about the axis of the trunnions 21 and 23 and through the connecting bar 49 similar rotation to the other roller housing. During this rotation of the roller housings the rollers 35 bear -upon and roll along the track 22 and the rollers 39 bear against and roll "along the substantially horizontal flange 32 of the angie member 3|. The door is consequently lifted vertically above the track 22 and supported for movementl along the track by means of the main rollers 35. Lifting of the door is permitted by the vertical slots 29 and 33. It will be observed that during the rotation of the roller housings 26 the angular movement of the rollers 35 is equal in amount and opposite in direction to the angular movement of the rollers 33 and since the distance from the trunnions to the pins 38 is equal to the distance from the trunnions to the pins 42 the moment of the weight of the door upon the rollers 39 is equal to the moment of the force exerted by the main rollers 35 against the track 22. This relationship of the moments occurs throughout the entire lifting movement of the door and results in the substantial elimina.- tion of friction between the trunnions and the slots which occurs in similar known lifting devices.

During movement of the operating lever 43 the door will continue to rise until the lever and the roller housings assume a substantially vertical position. At this time the lift of the door is a maximum. Continued movement of the lever in clockwise direction will cause the door to be lowered. This operation of the lever and lowering movement of the door is secured preferably when the door is in its full open position, whereupon the handle 45 will be in position to readily move the lever counter-clockwise in order to lift the door and support it for movement in closing direction. The mechanism is thus doubleacting and makes it possible to more readily lift and move the door regardless of the direction in which it is moved.

According to the instant invention, the desired inclination of the roller housings and lever when the door is lowered is obtained by the cooperation between the connecting bar 48 andthe cross bars 48--48 of the roller housings ,26-26. As more clearly shown in Fig. 1 of the drawing, engagement occurs between the connecting bar 46 and the cross bar 43 of the left hand roller housing when the door is in its lowered and closed position in order to limit the inclination of the roller housings and the lever. Similarly, when the door has been moved toward the right and is in its lowered and open position the connecting bar 46 will engage the cross bar 48 of the right hand roller housing to limit the inclination of the roller housings and the operating lever.

It will be apparent that numerous changes and modifications in the details of the invention will be clear to those skilled in the art. It is intended, therefore, that all such modifications and changes be comprehended within Ithis invention, which is to be limited only by the scope of the claims appended hereto.

I claim:

1. Lifting mechanism for a sliding door adapted to be frictionally supported in lowered position by a track comprising spaced, inclined roller housings, alined trunnions on each housing adapted to extend into slots formed in said door, rollers mounted on each housing equi-distantly above and below said trunnions, flanges adapted to be secured to said door above the upper rollers for engagement thereby to lift said door, said lower rollers being adapted to bear against said track during lifting engagement of said upper rollers and said flanges. an operating lever mounted upon one of said trunnions and means connecting said housings for simultaneous operation.

2. Lifting mechanism for a sliding door adapted to be frictionally supported in lowered position by a track comprising an inclined roller housing, alined trunnions on said housing adapted to extend into slots formed in said door, rollers mounted on said housing equi-distantly above and below said trunnions, a flange adapted to be secured to said door above the upper roller for engagement thereby to lift said door, said lower roller being adapted to bear against said track during lifting engagement of said upper roller and said flanges and means mounted on one of said trunnions for imparting rotation to said housing about the axis of said trunnions, the angular displacement of said rollers during rotation of said housing being equal in amount and opposite in direction.

3. Lifting mechanism for a sliding door adapted to be frictionally supported in lowered position by a track comprising spaced, inclined substantially H-shaped roller housings, alined trunnions on each housing adapted to extend into slots formed in said door, a roller mounted between the branches of said housings above the cross bar thereof, a roller mounted between the branches of said housings below said cross bar, said rollers lying on opposite sides of and equidistantly from said trunnions, flanges adapted to be secured to said door above the upper rollers for engagement thereby to lift said door, said lower rollers being adapted to bear against said track during lifting engagement of said upper rollers and said flanges an operating lever mounted upon one of said trunnions and means connecting said housings for simultaneous operation.

4. Lifting mechanism for a sliding door adapted 40.to be frictionally supported in lowered position by a track comprising spaced, inclined substan tially H-shaped roller housings, alined trunnions on each housing adapted to extend into slots formed in said door, a roller mounted between the branches of said housings above the cross bar thereof, a roller mounted between the branches of said housings below said cross bar, said rollers lying on opposite sides of and equi-distantly from said trunnions, flanges adapted to be secured to said door above the upper rollers for engagement thereby to lift said door, said lower rollers being adapted to bear against said track during lifting engagement of said upper rollers and said flanges an operating lever mounted upon one of said trunnions and means connecting said housings for simultaneous operation, said connecting means engaging a cross bar of one of said housings to determine the position of said lever when said door is lowered.

5. Lifting mechanism for a sliding door adapted to be frictionally supported in lowered position by a track comprising spaced, inclined roller housings, alined trunnions on each housing adapted to extend into slots formed in said door, rollers mounted on each housing equi-distantly above and below said trunnions, flanges adapted to be secured to said door above the upper rollers for engagement thereby to lift said door, said lower rollers being adapted to bear against said track during lifting engagement of said upper rollers and said flanges an operating lever mounted upon one of said trunnions, means connecting said housings for simultaneous operation, and means on one of said housings engaging said connecting means to determine the po` DEUUH sition of said lever when said door is lowered.

8. Lifting mechanism for a sliding door adapted to be frictionally supported in lowered position by a track comprising spaced, inclined roller housings, alined trunnions on each housing adapted to extend into slots formed in said door, rollers mounted on each housing equi-distantly above and below said trunnions, flanges adapted to be secured to said door above the upper rollers for engagement thereby to lift said door, said lower rollers being adapted to bear against said track during lifting engagement of said upper rollers and said ilanges an operating lever mounted upon one of said trunnions and means connecting said housings for simultaneous operation, said lever being movable in the direction of movement of said door to lift said door.

7. Lifting mechanism for a sliding door adapted to be frictionally supported in lowered position by a track comprising an inclined roller housing, alined trunnions on said housing adapted to extend into slots formed in said door, rollers mounted on said housing equi-distantly above and below said trunnions, a flange adapted to be secured to said door above the upper roller for engagement thereby to lift said door, said lower roller being adapted to bear against said track during lifting engagement of said upper roller and said flanges and means mounted on one of said trunnions for imparting rotation to said housing about the axis of said trunnions, the angular displacement of said rollers during rotation of said housing being equal in amount and opposite in direction, said means being movable inthe direction of movement of said door to lift said door.

FRANK DITCHFIELD. 

